You also have to consider: Are you going to drive all the drivers together, or are you going to use crossovers (actually, peaked bandpass filters) to drive each one with only its designed frequency?
Somewhere in the dark recesses of my mind where not even a candle has fluttered for many years I seem to recall that there was metal plate above the jug but instead of having a straight cut circle through the plate there was a fairly long radial taper - thinnest at the opening and gradually opening to full plate thickness, which was quite thin. Would this act like a reed? How does a reed act? Is it just vortices from the thinnest part or edge or are there other harmonics -sub harmonics as the reed gets thicker. I am thinking of a saxaphone reed here. Maybe the combination of the reed and the tapered port acts like a reed musical instrument?
If that could happen it might not give a lone tone that is pure to the recording but as I understand it who is going to know that low down?
jamikl
If that could happen it might not give a lone tone that is pure to the recording but as I understand it who is going to know that low down?
jamikl
Turbulence
Fan noise and turbulence are extremely low and when music
is playing can not be heard. The rotary subwoofer has a
low pass xover (set at 25 hz, 18 db per octave) and the
Magneplanar bass panels are good to below 30 hz. A excellent
match and the two are coherent and both have transient
response that rivals most, if not all. A Mark Levinson 380S
preamp is utilized for balancing the output of Maggie bass
panels (volume control has .1 db increments)
Fan noise and turbulence are extremely low and when music
is playing can not be heard. The rotary subwoofer has a
low pass xover (set at 25 hz, 18 db per octave) and the
Magneplanar bass panels are good to below 30 hz. A excellent
match and the two are coherent and both have transient
response that rivals most, if not all. A Mark Levinson 380S
preamp is utilized for balancing the output of Maggie bass
panels (volume control has .1 db increments)
Attachments
I have read the whole thread but i didn't get whether i should try it or not, please suggest me i want to try it, should i try it ? i am currently using 12inches (w), 30 inches (H) and 17 inches (Depth)box with 10" woofer with sealed configuration, should i expect better than this from GHVCIBS ?
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Holliman build pictures
Hi All,
Managed to get them together -
http://dl.dropbox.com/u/9601432/DSCF1953.JPG
http://dl.dropbox.com/u/9601432/DSCF1980.JPG
http://dl.dropbox.com/u/9601432/DSCF1984.JPG
http://dl.dropbox.com/u/9601432/DSCF1988.JPG
http://dl.dropbox.com/u/9601432/DSCF1991.JPG
Will give more detailed feedback on performance soon, got an Inphase driver in at the moment, needs testing on a little smaller excursion cone I reckon, but does drop very low, but very narrow sensible range
Hi All,
Managed to get them together -
http://dl.dropbox.com/u/9601432/DSCF1953.JPG
http://dl.dropbox.com/u/9601432/DSCF1980.JPG
http://dl.dropbox.com/u/9601432/DSCF1984.JPG
http://dl.dropbox.com/u/9601432/DSCF1988.JPG
http://dl.dropbox.com/u/9601432/DSCF1991.JPG
Will give more detailed feedback on performance soon, got an Inphase driver in at the moment, needs testing on a little smaller excursion cone I reckon, but does drop very low, but very narrow sensible range
Wow! thanks paul !! i heard about this Box for many times but this is for the first time i have seen real pics of it ! many many thanks mate
GH mentioned that the hole "Y" should be made on a very thin sheet of Formica or Duralumin, and panel "K" should be fixed on panel "C" you have put it on "D". Thanks for sharing pics, i will be waiting for your feedback on performance !
@ paulronanqed
Nice to see someone Actually building one
What driver are you using ?
Earlier on in this thread i posted several things about it. And that i purchased the plans way back when. I seem to recall that this gap was a lot smaller in the plans ?
Have you modified the original design ? or is my memory fading
Looking forward to some test results on this
Regards
Nice to see someone Actually building one
What driver are you using ?
Earlier on in this thread i posted several things about it. And that i purchased the plans way back when. I seem to recall that this gap was a lot smaller in the plans ?
Have you modified the original design ? or is my memory fading
Looking forward to some test results on this
Regards
Wow! thanks paul !! i heard about this Box for many times but this is for the first time i have seen real pics of it ! many many thanks mate
GH mentioned that the hole "Y" should be made on a very thin sheet of Formica or Duralumin, and panel "K" should be fixed on panel "C" you have put it on "D". Thanks for sharing pics, i will be waiting for your feedback on performance !
Ouch !!!!! The standing wave inserts !!!!! Thanks for the heads up, Just had a look at it and reckon I'll plough a rebated panel out of the front and remove and re-place the guides. On the back panel, I'm going to route out the circle leaving a 1/4 inch of the MDF and see how it goes, I put the spacer on the back as a temporary measure.
Will post more pickies of the rejigged and completed box over the next week or so, weather permitting (being built on my drive)
Thank you so much for everyones feedback, much appreciated, have a graet Christmas
Hi Zero D@ paulronanqed
Nice to see someone Actually building one
What driver are you using ?
Earlier on in this thread i posted several things about it. And that i purchased the plans way back when. I seem to recall that this gap was a lot smaller in the plans ?
View attachment 256667
Have you modified the original design ? or is my memory fading
Looking forward to some test results on this
Regards
I worked everything on the panel sizes +/- the bevel cuts and centralized the inner box / chamber, never really thought to check the throats as assumed that they would default to being correct. I'm just looking at the drawing now and seem to remember the throats being identified as 'x' or 'y' on another drawing somewhere, the drawing I used has not got these on, but I've followed the measurements on the table, looks roughly in proportion.Its a very good point you raise though I'll have a look, I can import the drawing to cadmeasure and scale them off. I've attached the drawing I used.
An externally hosted image should be here but it was not working when we last tested it.
On the driver, I'm using a 15" 1800w Inphase, but feel while listening that there is an optimum, most likely determined by the small throat, that is being passed the longer the extension of the cone. There has been suggestion on here that a small excursion cone is best, from what I've heard of this box, I'm more likely to go for an Eminence Kappa Pro LF 15 that I have.
Any suggestions of a more appropriate cone would be much appreciated.
Many thanks
I agree, and when pushed with a long throw passes optimum, I'm wary of fundamentally changing anything to do with the design, thinking I may opt for shorter throw, then maybe drop a rebated panel in with varying throats to see what impact it has, will keep you posted.
It can't be modeled in Hornresp but IIRC at some point someone modeled the 10 inch version in Akabak. It wasn't very impressive, certainly no infrabass. That's when I lost interest.
It did go fairly low though, but as always the cost of going low is driver displacement, and with the small throat you really limit how much displacement you can use. Unfortunately it's not a magic box and for my money there's better ways to make bass in this computer age.